21776678784 has 144 divisors (see below), whose sum is σ = 72895815720. Its totient is φ = 6221892096.

The previous prime is 21776678773. The next prime is 21776678821. The reversal of 21776678784 is 48787667712.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 136444 + ... + 249339.

Almost surely, 2^21776678784 is an apocalyptic number.

21776678784 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21776678784 is an abundant number, since it is smaller than the sum of its proper divisors (51119136936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21776678784 is a wasteful number, since it uses less digits than its factorization.

21776678784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385817 (or 385795 counting only the distinct ones).

The product of its digits is 44255232, while the sum is 63.

The spelling of 21776678784 in words is "twenty-one billion, seven hundred seventy-six million, six hundred seventy-eight thousand, seven hundred eighty-four".